WASHINGTON — Air Force investigators have identified 31 female trainees who are alleged victims of military training instructors in growing sexual abuse and misconduct scandal at Lackland Air Force Base in San Antonio, officials said Thursday.

Twelve male instructors have been accused of offenses ranging from seeking improper relationships to rape. Nine of the 12 were from a single unit at the base, the 331st Training Squadron, said Gen. Edward Rice Jr., commander of the Air Force’s Air Education and Training Command.

“In my assessment to this point, it is not an issue of an endemic problem throughout basic military training,” Rice said. “It is more localized and we are doing a very intensive investigation on that squadron to find out what exactly happened and why.”

The unit commander, Lt. Col. Mike Paquette, was removed from command earlier this month because of the problems in his unit and remains on administrative hold, awaiting another assignment, Rice said.

The scandal came to light last June when a trainee reported suspected sexual misconduct. That fall, a group of three male and female instructors came forward with further incriminating information. Only one of the twelve suspected instructors, Staff Sgt. Peter Vega-Maldonado, has been convicted for having an improper relationship and violating a no-contact order. He is serving a 90 day jail sentence. After his release, he will be discharged from the Air Force at the rank of airman, Rice said.

Two other airmen were charged this week for sexual improprieties, and Rice said the Air Force is investigating the possibility of more victims and more trainers involved. Last week, he appointed Maj. Gen. Margaret Woodward to lead a comprehensive investigation of Air Force training.

“I’m not minimizing this investigation, in fact I’m being as aggressive as I can,” he said. “We won’t stop the investigation until I am completely satisfied we have done as thorough a job as we possibly can.”